The Harlington-Straker film studios appear to the outside world to be rather glamourous buildings in and around which exciting and profitable movies are made. Yet, beneath those same buildings is a vast network of tunnels and halls, offices and laboratories where the top secret and vitally important work of SHADO is controlled.

The massive underground complex is the headquarters and nerve centre of the fight against the dreaded Aliens from a planet somewhere in deep space, a dying race of humanoids who have defied time and distance in their search for replacement organs necessary to prolong their existence.

Billions of dollars have been appropriated to the SHADO operation from every country in the world, for the battle against the powerful UFO machines and their sinister pilots is peculiar to no one race or creed. The whole world is under the threat of the invading Aliens who strike regularly in all parts of the globe.

For ten long years, SHADO's Supreme Commander, Ed Straker nursed the building and formation of the defence systems, and despite many setbacks and personal tragedies during that period, he remained completely dedicated to his duty to protect the Earth.

Time, money, effort and worry were required to make SHADO operational, but the best laid defences are not entirely impregnable. On the odd occasion the superior intelligence and strength of the Aliens throws SHADO Headquarters into moments of sheer panic and extreme danger!

There was the time when two UFO's eluded the highly sophisticated tracking systems of Moonbase and SID, the Space Intruder Detector satellite, and managed to land uncomfortably close to the film studios.

Two Aliens, whose mission was obviously centred on the destruction of SHADO Headquarters, came very close to achieving their aims when they managed to gain entry into SHADO Headquarters access corridors that lead to the vital main control centre.

Bravery and guile, organisation and instant decision making were the qualities called upon by the hundreds of SHADO personnel, and only after valiant efforts in all these departments of human endeavor were the Aliens finally trapped on the roof tops of the film studios' outlying buildings.

A similar crisis could develop at any time and the technicians, scientists, controllers and operatives at SHADO Headquarters must remain on constant alert for the danger signs.

Those highly trained SHADO staff members control the destinies of countless men, women and children who might fall innocent prey to the greatest enemy the world has ever known.

The valuable and complex machinery and equipment housed in the SHADO control centre is designed to save lives. And ironically, the very people it continues to protect can never be made aware of its function . . . for widespread knowledge of the SHADO operation and the Alien invasion could result in blind panic and total misunderstanding.

Ed Straker and his staff must wage a powerful and silent battle and their courage and devotion to duty must go unrewarded, for the SHADO password is 'secrecy'.